Mercury slip ring assembly



Dec. 19, 1961 D. J. LESLIE 3,014,192

MERCURY SLIP RING ASSEMBLY Filed Dec. 26, 1958 i 61'? 42 64 as 11 7 4 3747 55 4a 16 g5 4Z2 5 i k i1 29 1 E o 2 I IN V EN TOR.

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3,014,192 MERCURY SL1? RING ASSEMBLY Donald J. Leslie, Electra Music,313 S. Fair Oaks Ave,

Pasadena, Calif. Filed Dec. 26, 1958, Ser. No. 783,012 Claims. (Cl.339--5) This invention relates to speaker structures and particularly tospeakers for electronic organs in which tremulant is added acoustically.Devices of this general character are shown and described .in my priorPatents No; 2,489,653, issued November 29, 1949, entitled RotatableTremulant Sound. Producer, and No. 2,618,352, issued November 18, 1952,also entitled Rotatable, Tremulant Sound Producer.

In, some instances, tremulant is added by the aid of a rotary soundchannel or reflector plate cooperable- With a stationary speaker. Inother instances, the speakers themselves are rotated. One disadvantageof rotating speakers is that brush structures are required to maintainconnections as the speakers are rotated. Maintenance of brushes hasheretofore been a substantial problem.

The primary object of this invention is to provide a simple,self-contained, detachable slip ring structure cooperable in a simplemanner with a rotary shaft by the aid, of which connections to rotaryspeakers are readily established and maintained.

It is another object of. this invention to provide; a simplified, slipring structure that is readily removable.

Still another object of this invention is to provide an improved mercuryslip-ring structure in which the mercurypools are effectively contained.

In some instances, it is desirable to provide separate connections to apair of speakers, both mounted, upon a common support. For example, onereason for this'may be to maintain electrical segregation betweenimpulses corresponding to tones in alternate half-tone relationship withrespect to each other in order to avoid-certain beat effects asdescribed, for example, inmy prior Patent No. 2,596,258, issued May 13,1952, and entitled Electric Organ Speaker System.

It is, accordingly, an object of this invention to provide a si'mplestructure in which separate slip rings of identical construction may beused to establish separate speaker connections and by cooperation withopposite ends of a shaft.

This invention possesses many other advantages, and has other objectswhich may be made more clearly apparent from a consideration of oneembodiment of the invention. For this purpose, there is shown a form inthe drawings accompanying and formingpart of the present specification.This form will now. be described in detail,

illustratingthe general principles of the invention; but

FIGURE 1 is a fragmentary sectional view of a speaker enclosure togetherwith a rotary speaker, structure. therein and incorporating the presentinvention;

FIG. 2is an enlarged-view of a portion of the apparatus illustrated inFIG. 1;.

FIGS. 3, 4, 5 and 6 are sectional views taken along planescorresponding, respectively, to lines 33, 44, 5-5 and 6-6 of FIG. 2.

In FIG. 1 there is illustrated a speaker cabinet 10 in which a rotaryspeaker assembly 11 is mounted for purposes of adding tremulant.acoustically.

The speaker assembly 11 is in the form of a drum having, in thisinstance, upper andrlower circular walls 12 and 13 between which a'generally cylindrical wall 14 is supported. The cylindrical wall 14, inthis instance,

has two diametrically disposed openings 15 and 16. Speakers 17 and 18,located within the speaker assembly 11, are mounted, respectively, atthe openings 15 and 16 in a suitable manner.

The speaker assembly 11 is mounted for rotation by the aid of a shaft19'. Mounting collars 20 and 21 carried by the shaft have flanges 22 and23 fastened, respectively, to the outer sides of the upper and lowerwalls 12 and 13.

The shaft 19 is supported by the aidof a pair of ball bearing structures24" and'25 at opposite ends. Inner races of the bearings 24 and 25 areaccommodated upon reduced extensions 26 and 27 formed at the ends of theshaft 19. The outer races of the bearing structures 24' and 25- aresupported upon interior partition walls 28 and 29 forming a part of thespeaker enclosure 10. The shaft extensions 26 and 27 project beyond thebearings and the walls 28 and, 29 for access and for purposes to bepresently described. v

The upper end of the shaft 19 forms a means for establishing twoconnections to one of the speakers 17 and in cooperation with aremovable slip ring unit 30'. The construction of the upper end of theshaft 19 is illustrated clearly in FIG. 2.

The shaft 19 has an axial recess 31 extending inwardly from its end. Inthis recess an insulation sleeve 32 is fitted. Projecting upwardlythrough the insulation sleeve 32 andheld thereby is the bared end 33 ofa conductor 34.. The conductor 34 extends into the lower end of thesleeve 32' by way of an access slot 35 .(see also- FIG. 6) locatedbeneath the bearing 25 and intersecting the inner end offthe recess 31.The conductor 34f'extends 120.0116 of the terminals 36' of the speakerstructure. 17' and as illustrated in FIG. 1.

The shaft 19, which is made of conductive material, serves. as a commonor ground connection cooperable' with the other terminal 37 of thespeaker structure 17. For thispurpose,. a conductor 38 has one baredend39 cooperable with a screw 40 threadedly. accommodated in a laterallydisposed recess 41 of the shaft 19; The other end of' the conductor 38is secured to the terminal 37' and as illustrated in FIG. 1.

The. slip ring unit 30, has one end 42provided with a reduced extension.43. received in an enlarged outer end 44- of the shaft recess 31 to forma detachable connector thatcauses the unit 30 to rot'atewith the shaft19.

The upper end of the, shaft extension 257 is diametrically slotted, asat45 (see also FIG. 5), whereby a frictional grip is established betweenthe peripheral, portion of the reduced extension 43 of the slip ring 30-and the shaft 19.

The slip ring part 42. has a through bore 46 substantially enlarged atits upper end, as at 4 7, to form an upwardly opening recess. Auvinsulation sleeve, 48 is fitted in the bore 4-6. Thesleeve extendsupwardly from the end of the extension 43- intothe recess 47.. Acircular space within the upper end of the sleeve 48 and anannular space49,. electrically isolated therefrom betweenthe recess 47, and thesleeve 48, are. thereby formed.

Press-fitted in the lower portion of theinsul'ationsleeve 48 isa.conducting rod Sit-having a downwardly opening socket 51 in which theupper endof. the. conductor 331s received. The sleeve 48 abutstheupper-end-of the shaftmountedsleeve 32 when the parts are engaged.

A mercury pool 52: isaccommodated: in: the: sleeve. 48 above therod 5i),and iti's, of course, in electrical conducting'relationship with thesocket 51 and the conductor end 33. The mercury pool 521'selectricallyi'solat'edfrom; the shaft 19'and the part 42 by the sleeve48'. The rod 50 likewise abuts the upper end of the shaft mountedinsulation sleeve 32 and well within the peripheral boundary of thesleeve 32 to ensure electrical isolation with-respect to the shaft 19.

The annular space 49 of the slip ring part 42 accommodates a secondmercury pool 53 forming a liquid slip ring, that is electrically commonto the other conductor 38, a conductive path being established from thepool via the part 42, reduced extension 43, the upper shaft exten sion27, terminal screw 40, and the bared conductor end 39.

The slip ring unit 30 has an upper non-rotary part 54 provided withconductive projections or pins 55 and 56 respectively cooperable withthe mercury pools 52 and 53 whereby external connections areestablished. Conductive relationship between the pools and the pins 55and 56 (see also FIG. 4) is maintained despite rotation of the slip ringpart 42 by virtue of the fluid characteristics of the pools 52 and 53.

The part 54 includes an elongate tubular element 57 from the lower endof which the pin 56 eccentrically projects. The tubular part 57 and theslip ring part 42 are mutually supported for relative rotation withrespect to each other by the aid of a thrust ball bearing structure. Theinner race 58 of the bearing structure is fitted upon the lower end ofthe tubular part 57. The bearing structure has an outer race 59press-fitted within a cylindrical flange 60 extending upwardly from andformed integrally with the lower part 42. Upper and lower seal rings 61and 62 enclose balls 63 of the bearing structure cooperable respectivelywith the inner and outer races 58 and 59 for containing lubricant. Thebearing structure abuts the upper end surface 64 of the part'42 that islocated within the flange 60, and the lower end of the tubular part 57together with the inner race 58 closes the upper end of the recess 47.

For supporting and insulating the pin 55, an insulation sleeve 65 isprovided. This sleeve extends throughout the length of the bore in thetubular part 57. The conducting pin 55 is formed at the end of a rod 66pressfitted Within the sleeve 65. The rod 66 and the tubular part 57thus together provide conductive paths to the speaker leads 34 and 38. Adetachable jack 68 cooperates with a socket 67 in the upper end of therod 66 and with part 57 to provide connections to an exterior circuit.

The jack 68 is in the form of a cap 69 made of molded insulatingmaterial. It provides a recess 70 in which the upper end of the tubularpart 57 is received. One conductor 71 is mounted by the cap 69 andextends radially from an area. adjacent the outer end of the recess 79.The conductor 71 has a circular end 72 (FIG. 3) extending about andslightly into the recess 76, there being an annular groove 73 mountingthe conductor end 72. The conductor end loop 72 is expanded outwardly topermit passage of the tubular part 57 into the recess 70. A firmfrictional engagement between the conductor end loop 72 and the tubularpart 57 is established for an appropriate 7 electrical conductiverelationship.

The cap 69 also mounts a second conductor 74 that projects inwardly ofthe recess 70 through its inner end for detachable reception into thesocket 67.

As the shaft 19 is rotated, as, for example, by the aid of a pulley 75mounted upon the shaft, a belt 76, and a motor-driven pulley 77, theslip ring part 42 together with the mercury pools 52 and 53 are bothrotated. The tubular part 57 remains stationary, the bearing structure5859-63 appropriately permitting this relative motion. A connection isestablished to an external circuit as from the output of a poweramplifier by the aid of the separate conductors 71 and 74 of the jack68.

The quantity of mercury introduced into the recess 47 is carefullycontrolled to ensure that the level of the outer mercury pool 53 issubstantially beneath the upper end of the insulation sleeve 48 to avoidany short-circuiting relationship between the two mercury pools.

For purposes of installation of an organ speaker in cooperation with anelectronic organ, it is merely necessary that the jack 68 be provided atthe end of a twin conductor 78 extending from the power amplifier. The

4 jack is simply slipped upon the tubular part 57. Should it be deemednecessary or desirable to remove or replace the slip ring unit 54, thisis readily accomplished by simple axial separations.

The unit 54 can also be used reversibly, that is, at the lower end ofthe shaft. But the recesses for the mercury pools must be upwardlyoriented. This is possible since the rod 50 provides a socket equal indimension to that of the rod 66, and the tubular part 57 corresponds indimension to that of the reduced extension 43 of the part 42.

As illustrated in FIG. 1, a second slip ring unit 3011 is thus used atthe lower end of the shaft 19 and for purposes of establishingconnections to the other speaker 18. The lower shaft extension 26 isformed in the identical fashion as the upper shaft extension 27. Thus,it provides a socket that may cooperate with the tubular part 57 of thepart 54. The reduced extension 43 of the part 54a in this instancedetachably cooperates with a jack 68a that is identical to the jack 68.In this instance, the tubular part 57 and the pins 55 and 56 rotate withthe shaft 19, and, instead, the slip ring unit part 42 is non-rotary.Connections are readily established to a twin conductor 79, and separateelectrical connections to the respective speakers 17 and 18 areexpeditiously provided.

In order to avoid confusion as to the internal orientation of therecesses for the mercury pools, the part 42 has a conical configurationadjoining the extension 43. This also reduces the bulk of the unit as awhole.

Once assembled, the slip ring unit 54 requires no special handling. Therecess accommodating the inner mercury pool 52 has only slight clearancewith respect to the pin 55, and the surface tension of the mercuryensures that an adequate mercury pool remains within the sleeve 48despite jarring or actual inversion of the unit during shipment. Theouter mercury pool 53 assumes its appropriate orientation as soon as theunit is installed, and the entire recess 47 in which the mercury poolsare accommodated is'entirely sealed to prevent any mercury from escapingtherefrom.

The inventor claims:

1. In a slip ring connector structure: two electrically conductivemembers; bearing means supporting the members for relative rotationabout an axis; said members having interior surface means defining anenclosed space encompassing the said axis of rotation; a firstinsulation sleeve of uniform cross-section concentrically mounted by oneof the members and extending from an exterior boundary of said onemember and with clearance into said enclosed space to form a circularlyextending channel about the inwardly projecting end of said firstinsulation sleeve; a second insulation sleeve of uniform crosssectionconcentrically mounted by the other of said members and extending froman exterior boundary of said other member to a position accessible tothe said enclosed space; an electrically conductive pin mounted withinthe first insulation sleeve and terminating within the inner end of saidfirst insulation sleeve; a second electrically conductive pin mountedwithin the second insulation sleeve and projecting with clearance intothe inner end of said first insulation sleeve; said other conductivemember having a projection spaced from said axis of rotation andextending with clearance into said circularly extending channel; amercury pool in the circularly extending channel and in contact withsaid projection; and a second mercury pool in the inner end of said oneinsulation sleeve; the outer ends of said pins having exteriorlyaccessible, axially extending surfaces; said conductive members alsohaving exteriorly accessible, axially extending surfaces spaced fromthose of the corresponding pins for providing an electrical andmechanical connection by axial movement with a connector or the like.

2. The combination as set forth in claim 1 in which the level of themercury pool in the circularly extending channel is substantially belowthe inner end of said first sleeve when said axis is vertical, the saidfirst sleeve having clearance with respect to said second pin adequateto cause surface tension to retain mercury in said first sleeve despiteinversion.

3. The combination as set forth in claim 1, in which said axiallyextending surfaces of said members are formed about oppositely extendingcoaxial cylindrical projections of the members, in which the exteriorlyaccessible axially extending surfaces of the pins are formed withininwardly extending coaxial cylindrical recesses therein; saidcombination further including a shaft of conductive material having arecess at one end detaehably receiving the projection of one of themembers, said shaft having a projecting insulated conductor received inthe exteriorly accessible recess of the corresponding pin; and a caphaving a recess detachably receiving the projection of the other member,said cap having a pair of conductive parts separately connected to thesaid projection and the corresponding pin at the recess of said pin.

4. The combination as set forth in claim 1 together with a shaft ofconductive material, and having an axial recess at one end receiving oneof the conductive members at its axially extending surface; aninsulation sleeve mounted in the bottom of said recess; and a conductorhaving a bared end extending through the sleeve and received in thecorresponding pin at its axially extending surface.

5. The combination as set forth in claim 1 together with a shaft ofconductive material, and having an axial recess at one end receiving oneof the conductive members at its axially extending surface; aninsulation sleeve mounted in the bottom of said recess; a conductorhaving a bared end extending through the sleeve and received in thecorresponding pin at its axially extending surface; an insulation caphaving a socket receiving the other of the conducting members at itsaxially extending surface; a conductive loop supported in the recess andengaging the axially extending surface of said other member; and aconductor mounted centrally of the cap and received in the correspondingpin at its axially extending surface.

References (Cited in the file of this patent UNITED STATES PATENTS263,829 Weston Sept. 5, 1882 1,170,388 Anschutz Feb. 1, 1916 1,667,660Gehm Apr. 24, 1928 2,424,545 Bard July 29, 1947 2,715,713 Seim Aug. 16,1955 2,719,279 Muckler Sept. 27, 1955

